Radiation detectors

Abstract

In gas detectors, such as may be used in computerized tomographic (CT) apparatus, it is necessary to provide electrical connections into the pressure vessel. Conventionally, these are by ceramic lead-throughs or similar. As gas detectors require an increasing number of individual detector elements, and therefore internal electrodes, the number of connections required increases and they are more closely spaced. This large number of connections can affect the integrity of the pressure vessel. This invention places a circuit board as a gasket between two parts of the pressure vessel, such as between a chamber and lid, so that conducting tracks on or in the circuit board provide the required connections. The invention is suitable for lead through for pressure vessels other than gas detectors of radiation.

What I claim is: 
     
       1. A pressure vessel having an aperture therein and including a connection means which comprises a circuit board, having conducting tracks, mounted in the aperture such that the conducting tracks form electrical connections between the inside and the outside of the pressure vessel. 
     
     
       2. A pressure vessel according to claim 1, comprising at least first and second parts, in which said circuit board is sandwiched between the first and second parts. 
     
     
       3. A pressure vessel according to claim 2 in which the first part comprises a casing member, having components within to which the electrical connections are made, and the second part comprises a lid member closing the casing. 
     
     
       4. A pressure vessel according to claim 2 including one or more sealing gaskets disposed between said parts and said circuit board to prevent leakage along the boundary therebetween. 
     
     
       5. A pressure vessel according to any of the preceding claims in which the circuit board is formed with conducting tracks formed between at least two adjacent layers. 
     
     
       6. A detector of penetrating radiation including a pressure vessel having at least one aperture therein, the pressure vessel to be filled with high pressure gas for ionisation by incident radiation, a plurality of electrodes disposed in the pressure vessel to form individual detector elements and a circuit board, having conducting tracks, mounted in the aperture so that the conducting tracks form electrical connections from the electrodes to the outside of the pressure vessel. 
     
     
       7. A detector according to claim 6 including a radiation transmissive window also mounted in said pressure vessel. 
     
     
       8. A detector of penetrating radiation including, a pressure vessel to be filled with a high pressure gas for ionisation by incident radiation, a plurality of electrodes disposed in the pressure vessel to form individual detector elements, and connection means making electrical connection from outside the pressure vessel to said electrodes, the connection comprising a laminated circuit board, having conducting tracks, formed between at least two layers thereof, there being also an aperture in the pressure vessel with the circuit board mounted therein such that conducting tracks form electrical connections between the inside and outside of said vessel. 
     
     
       9. A detector according to claim 8 in which the pressure vessel comprises at least first and second parts and said circuit board is sandwiched between said first and second parts. 
     
     
       10. A detector according to claim 9 in which the first part is a casing member enclosing said electrodes and the second part is a lid member closing said casing. 
     
     
       11. A detector of penetrating radiation comprising a pressure vessel enclosing a plurality of electrode plates defining detector cells, said vessel containing a detector gas under pressure and comprising a casing and a lid secured together to enclose said electrodes and contain said detector gas, said detector further comprising a laminated circuit board mounted and secured as a gasket between the casing and lid and having electrically conductive tracks which are between laminae of the board and make electrical connection between the outside of the pressure vessel and the electrode plates inside the vessel.